The present invention relates to a lever lock unit, and more particularly to a lever lock unit in which movement of the lever tumblers is such as to make forcing and manipulation: of the lock difficult to achieve.
The invention also relates to a key for use with such a lock.
Known lever locks are constructed so that when turning the lock key, the key seeks for the lever tumblers in order to move the levers to a lock-release position in accordance with a code on the key. This general principle, whereby the key seeks and actuates the lever tumblers as the key is turned is beset with many draw-backs.
One of these drawbacks is that turning of the key results in wear between key and lever tumblers, which results in wear marks on both key and lever tumblers in the passage of time. These marks can facilitate manipulation and forcing of the lock.
Another drawback is that a multi-key/tumbler system cannot be readily implemented in some lock units of this kind, due to the particular design of the lever tumblers.
German Patent Specification 394 690 (Deutsche Txc3xcrschliexcex2-er-Industrie Wilhelm Mxc3xcller) teaches a lever lock that includes a plate which, when moved, dogs a number of lever tumblers into a lock release position when the correct key is inserted. This relative movement between plate and lever tumblers, and also between plate and key, is a combination of linear movement and rotary movement. This does not avoid the drawback whereby wear marks are formed on the key and lever tumblers.
One object of the present invention is to provide a lever lock unit which is more secure than earlier known lock units or assemblies of this kind.
Another object is to provide a lever lock unit with Which a key/lever tumbler system,n can be easily included.
Another object of the invention is to provide a lock unit which can be constructed from a wide choice of materials.
Still another object of the invention is to provide a key that can be used with such a lock unit.
This object is achieved with a lever lock unit that is accommodated in a housing and includes a dogging element adapted to actuate a lock bolt, a plurality of lever tumblers that are actuable via the dogging element and movable relative thereto, and a blocking element for blocking movement of the dogging element when no key is inserted, or when the wrong key is inserted, wherein the lever lock unit is characterized by a cradle carried in the dogging element and adapted to accommodate the lever tumblers, wherein the dogging element is rotatable and so adapted that rotation of the dogging element will cause the cradle accommodated in the dogging element, and therewith the lever tumblers accommodated in the cradle, to move linearly in relation to the dogging element and in relation to a key inserted in the lock, so as to bring the lever tumblers to a blocking element release position when the correct key has been inserted.
The decisive difference between conventional locks in which the key seeks the lever tumblers and lifts the same and the inventive lock construction, is that in the case of the inventive lock construction the lever tumblers, instead, seek the key and stop in the position given by the code.
Another difference is that turning of the key causes the cradle to move linearly through the coaction of means provided thereon with corresponding means in one part or the other part of the fixed housing.
One of the advantages afforded by the invention is that wear between key and lever tumblers is minimized, thereby avoiding the easily read wear marks that a conventional key will leave on a lever tumbler when striking the same. This greatly increases security of the lock against unauthorized manipulation.
Minimization of key wear on the lever tumblers also enables key and tumblers to be made from a wider variety of materials.
The invention also relates to a lock according to claim 11 or claim 12. The key is adapted for use with a lock of the general principle defined in claim 1.
Further preferred embodiments of the invention are set forth in the following dependent claims.